Many techniques have been employed to produce integrated circuit packages. Beam lead, spider, flip chip and others are methods known to those skilled in the art. These known methods are expensive, not entirely reliable and require many separate and distinct processing steps.
For example, the chip and wire technique involves ultrasonic welding of a large number of extremely fine aluminum wires as leads to pads on the semiconductor chip. In the even that any one of these bonds is defective, the entire package would be rejected as a product.
It has previously been suggested by Wetmore in U.S. Pat. No. 3,243,211 that a heat activated, recoverable nonconductive plastic may be used to fasten or hold wire leads together. The heat recoverable material upon being heated will encapsulate and hold the wire leads or conductors in a fixed relative position. Such a construction would be impractical for the small components of an integrated circuit package.
It has also been suggested by Otte in U.s. Pat. No. 3,588,618 that a conductive metal with a shape memory may be used as a lead material. The lead will normally be bent to connect with a second lead at a solder connection. Upon reheating the soldered connection to melt the solder, the leads will separate due to the shape memory effect of the particular alloy utilized to make the lead. As a result, components associated with the separated leads may be easily removed for repair or the like.
So far as it is known, however, no material or process has been devised utilizing the shape memory effect or similar effects for manufacture of integrated circuit packages. This invention is directed to such a process and product.